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1# ===========================================================================
2# Module versions
3# ===========================================================================
4#
5# Stage one of module building created the following:
6# a) The individual .o files used for the module
7# b) A <module>.o file which is the .o files above linked together
8# c) A <module>.mod file in $(MODVERDIR)/, listing the name of the
9# the preliminary <module>.o file, plus all .o files
10
11# Stage 2 is handled by this file and does the following
12# 1) Find all modules from the files listed in $(MODVERDIR)/
13# 2) modpost is then used to
14# 3) create one <module>.mod.c file pr. module
15# 4) create one Module.symvers file with CRC for all exported symbols
16# 5) compile all <module>.mod.c files
17# 6) final link of the module to a <module.ko> file
18
19# Step 3 is used to place certain information in the module's ELF
20# section, including information such as:
21# Version magic (see include/linux/vermagic.h for full details)
22# - Kernel release
23# - SMP is CONFIG_SMP
24# - PREEMPT is CONFIG_PREEMPT
25# - GCC Version
26# Module info
27# - Module version (MODULE_VERSION)
28# - Module alias'es (MODULE_ALIAS)
29# - Module license (MODULE_LICENSE)
30# - See include/linux/module.h for more details
31
32# Step 4 is solely used to allow module versioning in external modules,
33# where the CRC of each module is retrieved from the Module.symvers file.
34
35# KBUILD_MODPOST_WARN can be set to avoid error out in case of undefined
36# symbols in the final module linking stage
37# KBUILD_MODPOST_NOFINAL can be set to skip the final link of modules.
38# This is solely useful to speed up test compiles
39PHONY := _modpost
40_modpost: __modpost
41
42include include/config/auto.conf
43include scripts/Kbuild.include
44
45# When building external modules load the Kbuild file to retrieve EXTRA_SYMBOLS info
46ifneq ($(KBUILD_EXTMOD),)
47
48# set src + obj - they may be used when building the .mod.c file
49obj := $(KBUILD_EXTMOD)
50src := $(obj)
51
52# Include the module's Makefile to find KBUILD_EXTRA_SYMBOLS
53include $(if $(wildcard $(KBUILD_EXTMOD)/Kbuild), \
54 $(KBUILD_EXTMOD)/Kbuild, $(KBUILD_EXTMOD)/Makefile)
55endif
56
57include scripts/Makefile.lib
58
59kernelsymfile := $(objtree)/Module.symvers
60modulesymfile := $(firstword $(KBUILD_EXTMOD))/Module.symvers
61
62# Step 1), find all modules listed in $(MODVERDIR)/
63MODLISTCMD := find $(MODVERDIR) -name '*.mod' | xargs -r grep -h '\.ko$$' | sort -u
64__modules := $(shell $(MODLISTCMD))
65modules := $(patsubst %.o,%.ko, $(wildcard $(__modules:.ko=.o)))
66
67# Stop after building .o files if NOFINAL is set. Makes compile tests quicker
68_modpost: $(if $(KBUILD_MODPOST_NOFINAL), $(modules:.ko:.o),$(modules))
69
70# Step 2), invoke modpost
71# Includes step 3,4
72modpost = scripts/mod/modpost \
73 $(if $(CONFIG_MODVERSIONS),-m) \
74 $(if $(CONFIG_MODULE_SRCVERSION_ALL),-a,) \
75 $(if $(KBUILD_EXTMOD),-i,-o) $(kernelsymfile) \
76 $(if $(KBUILD_EXTMOD),-I $(modulesymfile)) \
77 $(if $(KBUILD_EXTRA_SYMBOLS), $(patsubst %, -e %,$(KBUILD_EXTRA_SYMBOLS))) \
78 $(if $(KBUILD_EXTMOD),-o $(modulesymfile)) \
79 $(if $(CONFIG_DEBUG_SECTION_MISMATCH),,-S) \
80 $(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E) \
81 $(if $(KBUILD_EXTMOD)$(KBUILD_MODPOST_WARN),-w)
82
83MODPOST_OPT=$(subst -i,-n,$(filter -i,$(MAKEFLAGS)))
84
85# We can go over command line length here, so be careful.
86quiet_cmd_modpost = MODPOST $(words $(filter-out vmlinux FORCE, $^)) modules
87 cmd_modpost = $(MODLISTCMD) | sed 's/\.ko$$/.o/' | $(modpost) $(MODPOST_OPT) -s -T -
88
89PHONY += __modpost
90__modpost: $(modules:.ko=.o) FORCE
91 $(call cmd,modpost) $(wildcard vmlinux)
92
93quiet_cmd_kernel-mod = MODPOST $@
94 cmd_kernel-mod = $(modpost) $@
95
96vmlinux.o: FORCE
97 $(call cmd,kernel-mod)
98
99# Declare generated files as targets for modpost
100$(symverfile): __modpost ;
101$(modules:.ko=.mod.c): __modpost ;
102
103
104# Step 5), compile all *.mod.c files
105
106# modname is set to make c_flags define KBUILD_MODNAME
107modname = $(notdir $(@:.mod.o=))
108
109quiet_cmd_cc_o_c = CC $@
110 cmd_cc_o_c = $(CC) $(c_flags) $(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE) \
111 -c -o $@ $<
112
113$(modules:.ko=.mod.o): %.mod.o: %.mod.c FORCE
114 $(call if_changed_dep,cc_o_c)
115
116targets += $(modules:.ko=.mod.o)
117
118# Step 6), final link of the modules
119quiet_cmd_ld_ko_o = LD [M] $@
120 cmd_ld_ko_o = $(LD) -r $(LDFLAGS) \
121 $(KBUILD_LDFLAGS_MODULE) $(LDFLAGS_MODULE) \
122 -o $@ $(filter-out FORCE,$^)
123
124$(modules): %.ko :%.o %.mod.o FORCE
125 $(call if_changed,ld_ko_o)
126
127targets += $(modules)
128
129
130# Add FORCE to the prequisites of a target to force it to be always rebuilt.
131# ---------------------------------------------------------------------------
132
133PHONY += FORCE
134
135FORCE:
136
137# Read all saved command lines and dependencies for the $(targets) we
138# may be building above, using $(if_changed{,_dep}). As an
139# optimization, we don't need to read them if the target does not
140# exist, we will rebuild anyway in that case.
141
142targets := $(wildcard $(sort $(targets)))
143cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))
144
145ifneq ($(cmd_files),)
146 include $(cmd_files)
147endif
148
149
150# Declare the contents of the .PHONY variable as phony. We keep that
151# information in a variable se we can use it in if_changed and friends.
152
153.PHONY: $(PHONY)
1# SPDX-License-Identifier: GPL-2.0
2# ===========================================================================
3# Module versions
4# ===========================================================================
5#
6# Stage one of module building created the following:
7# a) The individual .o files used for the module
8# b) A <module>.o file which is the .o files above linked together
9# c) A <module>.mod file, listing the name of the preliminary <module>.o file,
10# plus all .o files
11# d) modules.order, which lists all the modules
12
13# Stage 2 is handled by this file and does the following
14# 1) Find all modules listed in modules.order
15# 2) modpost is then used to
16# 3) create one <module>.mod.c file per module
17# 4) create one Module.symvers file with CRC for all exported symbols
18
19# Step 3 is used to place certain information in the module's ELF
20# section, including information such as:
21# Version magic (see include/linux/vermagic.h for full details)
22# - Kernel release
23# - SMP is CONFIG_SMP
24# - PREEMPT is CONFIG_PREEMPT[_RT]
25# - GCC Version
26# Module info
27# - Module version (MODULE_VERSION)
28# - Module alias'es (MODULE_ALIAS)
29# - Module license (MODULE_LICENSE)
30# - See include/linux/module.h for more details
31
32# Step 4 is solely used to allow module versioning in external modules,
33# where the CRC of each module is retrieved from the Module.symvers file.
34
35PHONY := __modpost
36__modpost:
37
38include include/config/auto.conf
39include $(srctree)/scripts/Kbuild.include
40
41MODPOST = scripts/mod/modpost
42
43modpost-args = \
44 $(if $(CONFIG_MODVERSIONS),-m) \
45 $(if $(CONFIG_MODULE_SRCVERSION_ALL),-a) \
46 $(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E) \
47 $(if $(KBUILD_MODPOST_WARN),-w) \
48 $(if $(KBUILD_NSDEPS),-d $(MODULES_NSDEPS)) \
49 $(if $(CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS)$(KBUILD_NSDEPS),-N) \
50 -o $@
51
52modpost-deps := $(MODPOST)
53
54# 'make -i -k' ignores compile errors, and builds as many modules as possible.
55ifneq ($(findstring i,$(filter-out --%,$(MAKEFLAGS))),)
56modpost-args += -n
57endif
58
59# Read out modules.order to pass in modpost.
60# Otherwise, allmodconfig would fail with "Argument list too long".
61ifdef KBUILD_MODULES
62modpost-args += -T $(MODORDER)
63modpost-deps += $(MODORDER)
64endif
65
66ifeq ($(KBUILD_EXTMOD),)
67
68# Generate the list of in-tree objects in vmlinux
69# ---------------------------------------------------------------------------
70
71# This is used to retrieve symbol versions generated by genksyms.
72ifdef CONFIG_MODVERSIONS
73vmlinux.symvers Module.symvers: .vmlinux.objs
74endif
75
76# Ignore libgcc.a
77# Some architectures do '$(CC) --print-libgcc-file-name' to borrow libgcc.a
78# from the toolchain, but there is no EXPORT_SYMBOL in it.
79
80quiet_cmd_vmlinux_objs = GEN $@
81 cmd_vmlinux_objs = \
82 for f in $(real-prereqs); do \
83 case $${f} in \
84 *libgcc.a) ;; \
85 *) $(AR) t $${f} ;; \
86 esac \
87 done > $@
88
89targets += .vmlinux.objs
90.vmlinux.objs: vmlinux.a $(KBUILD_VMLINUX_LIBS) FORCE
91 $(call if_changed,vmlinux_objs)
92
93ifeq ($(wildcard vmlinux.o),)
94missing-input := vmlinux.o
95output-symdump := modules-only.symvers
96else
97modpost-args += vmlinux.o
98modpost-deps += vmlinux.o
99output-symdump := $(if $(KBUILD_MODULES), Module.symvers, vmlinux.symvers)
100endif
101
102else
103
104# set src + obj - they may be used in the modules's Makefile
105obj := $(KBUILD_EXTMOD)
106src := $(obj)
107
108# Include the module's Makefile to find KBUILD_EXTRA_SYMBOLS
109include $(kbuild-file)
110
111output-symdump := $(KBUILD_EXTMOD)/Module.symvers
112
113ifeq ($(wildcard Module.symvers),)
114missing-input := Module.symvers
115else
116modpost-args += -i Module.symvers
117modpost-deps += Module.symvers
118endif
119
120modpost-args += -e $(addprefix -i , $(KBUILD_EXTRA_SYMBOLS))
121
122endif # ($(KBUILD_EXTMOD),)
123
124ifneq ($(missing-input),)
125modpost-args += -w
126endif
127
128quiet_cmd_modpost = MODPOST $@
129 cmd_modpost = \
130 $(if $(missing-input), \
131 echo >&2 "WARNING: $(missing-input) is missing."; \
132 echo >&2 " Modules may not have dependencies or modversions."; \
133 echo >&2 " You may get many unresolved symbol warnings.";) \
134 $(MODPOST) $(modpost-args)
135
136targets += $(output-symdump)
137$(output-symdump): $(modpost-deps) FORCE
138 $(call if_changed,modpost)
139
140__modpost: $(output-symdump)
141PHONY += FORCE
142FORCE:
143
144existing-targets := $(wildcard $(sort $(targets)))
145
146-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
147
148.PHONY: $(PHONY)